1. Technical Field
The present disclosure relates to the field of signal processing, and more specifically, to spectral analysis.
2. Description of the Related Art
Spectral analysis is the process of decomposing a signal into a spectrum to analyze the signal characteristics at different frequencies. Typical spectral measurements are limited in dynamic range by electrical noise and distortion, some of which may be caused by the measuring instrument itself. This can be especially problematic in radio frequency (RF) spectral analysis, where a trade-off is usually made between distortion and noise performance by varying the amount of signal attenuation at the input of the instrument, which in turn varies the actual signal level in the instrument. Many spectrum analyzers are inefficient at separating a signal from random noise, resulting in little separation between the signal to be examined and noise, even when displayed on a log scale (decibels). An example spectral analysis on a 40 kHz tone, at −100 dB, with added noise and digitized at 1 MS/s is illustrated in FIG. 1. As shown, the noise is indicated at a displayed floor of −100 dB, biasing the tone up by 3 dB. In other spectrum analyzers, slightly improved separation exists but significant power is lost by dropping both the signal and noise floor down by approximately 2.5 decibels (dB).